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Loss of teeth increases with age or after genotoxic treatments, like head and neck radiotherapy, due to periodontium breakdown. Periodontal ligament fibroblasts represent the main cell type in this tissue and are crucial for the maintenance of homeodynamics and for its regeneration. Here, we have studied the characteristics of human periodontal ligament fibroblasts (hPDLF) that became senescent after replicative exhaustion or after exposure to ionizing radiation, as well as their ability for osteoblastic differentiation. We found that senescent hPDLF express classical markers of senescence, as well as a catabolic phenotype, as shown by the decrease in collagen type I and the increase of MMP-2 expression. In addition, we observed a considerably decreased expression of the major transcription factor for osteoblastic differentiation, i.e. Runx2, a down-regulation which was found to be p53-dependent. In accordance to the above, senescent cells have a significantly decreased alkaline phosphatase gene expression and activity, as well as a reduced ability for osteoblastic differentiation, as found by Alizarin Red staining. Interestingly, cells from both type of senescence express similar characteristics, implying analogous functions in vivo. In conclusion, senescent hPDLF express a catabolic phenotype and express a significantly decreased ability towards an osteoblastic differentiation, thus probably affecting tissue development and integrity. [ABSTRACT FROM AUTHOR]

Objective: We investigated the efficacy of locally applied nasal decongestant agents and corticosteroids for preventing nosocomial maxillary sinusitis in mechanically ventilated patients with multiple trauma.Design and Setting: A prospective, open-label randomized study in two intensive care units (ICUs).Patients: 79 consecutive multiple trauma patients admitted to the ICU who were expected to be mechanically ventilated for more than 3 days.Interventions: Patients were randomly assigned to receive either a combination of a locally applied nasal decongestant agents: 2 drops twice/day of xylometazoline nasal solution 0.1% and 100microg budesonide (NDCA group, n=39) or placebo (control group, n=40).Measurements: For the diagnosis of radiological maxillary sinusitis patients underwent paranasal computed tomography within 48h of admission and thereafter every 4-7 days. Infectious maxillary sinusitis was diagnosed by microbiological analysis of fluid aspirated after transnasal puncture of maxillary sinuses.Results: Radiological maxillary sinusitis was detected in 54% of patients in the NDCA group (n=21) but in 82% of controls (p<0.01), and infectious maxillary sinusitis in 8% of the NDCA group (n=3) but in 20% of controls (n=8; p=0.11). The most common pathogen micro-organisms identified from maxillary aspirates were Acinetobacter (32%) followed by anaerobes (21%).Conclusion: Our results indicate that the combination of locally applied xylometazoline hydrochloride and budesonide reduces the incidence of radiological maxillary sinusitis and may reduce also that of nosocomial maxillary sinusitis in mechanically ventilated patients with multiple trauma. [ABSTRACT FROM AUTHOR]

A response to a letter to the editor about the article on the study of the prevention of nosocomial maxillary sinusitis published in a previous issue of the periodical is presented.